Stabilized fuel oil compositions



United States Patent STABILIZED FUEL OIL COMPOSITIONS George A. Weisgerber, lselin, and John 0. Smith, In, North Plainfield, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application November 19, 1956 Serial No. 622,798

2 Claims. (Cl. 44-68) The present invention concerns the stabilization of petroleum hydrocarbon fuels against degradation in storage. The invention is particularly directed to the stabilization of petroleum distillates that are intermediate in volatility between gasoline and lubricating oils and that are employed primarily as diesel fuels and jet fuels and as fuels for domestic heating furnaces.

When distillate fuels of the above types include cracked stocks, that is, stocks derived from thermal or catalytic cracking operations, they tend to be unstable on storage, forming sediment or sludge. Suoh fuel oils also tend to be corrosive toward ferrous metals with which they come into contact particularly in the presence of water or of an atmosphere containing water vapor. Such corrosive tendencies are obviously undesirable as is the formation of sludge or sediment since the latter may cause plugging or fouling of the fuel lines, filters and nozzles of the burner systems in which the fuel oils are employed. The problems of sediment formation and corrosion arise particularly when the fuel oils contain at least ten percent of cracked stocks.

It is a primary object of the present invention to prove the stability of petroleum fuel oils as well as to eliminate or minimize the corrosive tendencies of such fuel oils. The invention is particularly applicable to fuel oils containing 10 percent or more of cracked stocks. Among the particular fuel oils embraced within the scope of the present invention are included those meeting the specifications for grade 1 and grade 2 fuel oils under A.S.T.M. Designation D39648T and diesel fuels No. lD, 2-D, and 4-D of A.S.T.M Designation D-975-5 l-T.

In accordance with the present invention, the degradation of distillate fuel oil compositions during storage and the corrosiveness of such fuel oils toward ferrous metals are prevented by incorporating in the fuel oil compositions minor proportions, of the order of about 0.001 to about 0.2%, preferably about 0.01 to about 0.1 percent, by weight of a mixture of a nitro phenyl alkyl thioether and an oil soluble zinc salt of a naphthenic acid or of a sulfonic acid.

The nitro phenyl alkyl sulfides (thioethers) suitable for use in this invention include mono nitrophenyl and dinitrophenyl derivatives and can conveniently be prepared by reaction of a nitro halo benzene such as dinitrochlorobenzene with an alkali metal salt of an alkyl mercaptan, as shown by the following reaction.

N0, No; I Similar thioethers can be prepared by reaction of l-chloro,

ICC

2-nitrobenzene or of l-chloro, 4-nitrobenzene with an alkyl mercaptan. Rin the above formula is preferably an alkyl group of from 8 to 24 carbon atoms. Thus, the octyl, decyl, dodecyl, tridecyl, octadecyl, etc., thioethers of mononitro and dinitrobenzenes can be used.

The zinc salt employed in this invention may be a salt of petroleum naphthenic acids of about 150 to 300 molecular weight or a salt of a sulfonic acid having a molecular weight of from 375 to 600. Salts of petroleum sulfonic acids or synthetic sulfonic. acids such as alkyl benzene sulfonic acids may be employed, as for example zinc didodecyl benzene sulfonate.

Preferably the thioether and the zinc salt are employed in the range of from about equal proportions to about 1% times as much of one component as the other, although the proportions may be in the range of from 3 parts of the thioether and 1 part of zinc salt, to 1 part of the thioether and 3 parts of the zinc salt.

The following examples serve to illustrate this invention.

EXAMPLE 1 Sodium octadecyl mercaptide was prepared by direct reaction-of 46.4 grams of octadecyl mercaptan with 3.7 grams of sodium. The reaction started slowly and after the sodium had been heated above the melting point. Once started, the reaction went very quickly and was complete in a few minutes. Then 2,4 dinitro phenyl octadecyl sulfide was prepared by reacting 30.8 grams of sodium octadecyl mercaptide with 20.2 grams of 2,4 dinitro chlorobenzene in boiling toluene for 2 hours. The sodium chloride formed was removed by filtration and the toluene by distillation. were obtained in each of the above reactions.

EXAMPLE 2 A commercial heating oil was selected for stability tests using the oil itself as well as mixtures of the oil with various additives, as will be explained below. The oil was a blend of 50% virgin heating oil and 50% cracked stock. Typical inspections of this type of fuel oil are as follows:

To various samples of the fuel oil were added the materials set forth in Table I below. The base fuel and each of the additive blends were subjected to a stability test which consisted in storing the fuel oil for a period of 16 hours while maintaining the temperature at 210 F. At the end of the 16 hours the fuel oil was filtered and the amount of sediment that had been formed during the storage period was quantitatively determined.

Other portions of the blends as well as the uninhibited base fuel were also subjected to a rusting test in which steel strips were immersed in a mixture of 10% water and fuel for a period of 12 days at room temperature. The appearance of the steel strips at the end of this period was noted. Table I sets forth the data obtained in each of these tests.

Essentially quantitative yields 3 Table l INHIBITION OF CRACKED HEATING OIL AGAINST SEDI MENT FORMATION AND RUSTING The zinc naphthenate employed in this test was one prepared from naphthenic acids of about 200 molecular weight.

It will be noted from Table I that zinc naphthenate didnot improve the sediment forming tendencies of the fuel oil but actually aggravated those tendencies. The dinitrophenyl alkyl sulfide inhibited sediment formation considerably and also reduced the rusting to some extent. The mixture of equal parts of the dinitrophenyl alkyl sulfide and zinc naphthenate in a total concentration equal to that used with the samples containing those additives alone was much superior in its action on reducing sediment formation and at same time completely inhibited rusting. Thus the mixture of the two additives was found to be more potent as an inhibitor than either component alone.

Although the specific tests reported above were conducted with a heating oil, it is also contemplated to add the mixture of additives to diesel fuel oils, where the mixture will not only serve to inhibit deterioration on storage, but the presence of the nitro groups in the additive mixture will serve to improve the cetane number of such fuels, while at the same time the presence of zinc will serve to improve the engine cleanliness properties of the fuel. The additive mixture may also be employed to improve the storage stability and other properties of jet engine fuels having vapor pressures lower than gasoline, as for example jet fuel JP-l, JP-4 or JP-S.

The following are representative examples of other compositions that may be employed in practicing this invention. In each case percentages are by weight.

(1) Heating oil of No. 2 grade containing about 0.01 percent nitrophenyl cetyl sulfide and about 0.015 percent of zinc salts of naphthenic acids of about 200 molecular weight.

(2) A JP-4 jet fuel containing about 0.003 percent of 2,4-dinitrophenyl tridecyl sulfide and about 0.002 percent of zinc petroleum sulfonates (sulfonic acids of about 380 molecular weight).

(3) A diesel fuel containing about 0.10 percent of zinc naphthenate and about 0.10 percent of 2,6-dinitro- 4-nonylphenyl octyl sulfide.

(4) A JP-S jet fuel containing about 0.008 percent of zinc di-dodecyl benzene sulfonate and about 0.01 percent of nitrophenyl iso-octyl sulfide. t

(5) A diesel fuel containing about 0.08 percent of zinc petroleum sulfonates and about 0.05 percent of 2,4- dinitrophenyl octadecyl sulfide.

(6) A No. 2 heating oil containing about 0.002 percent of 2-nitrophenyl tridecyl sulfide, about 0.002 percent of 2,4-dinitrophe'nyl tridecyl sulfide, about 0.005 percent of zinc naphthenate and about 0.002 percent of zinc petroleum sulfonates.

It is not intended that the scope of the invention be limited to the specific examples, which have been presented to illustrate the invention. The scope of this invention is defined in the following claims.

What is claimed is:

l. A petroleum distillate fuel oil including at least 10 percent of cracked hydrocarbons to which has been added from about 0.001 to about 0.2 percent by weight of a mixture of from 1 to 3 parts of dinitrophenyl octadecyl sulfide and from 1 to 3 parts of a zinc salt of a petroleum naphthenic acid having a molecular weight of from about to about 300.

2. A fuel as defined by claim 1 wherein said mixture is present in a concentration of from about 0.01 to 0.1 percent by weight.

References Cited in the file of this patent UNITED STATES PATENTS 1,988,300 Clark Jan. 15, 1935 2,134,432 Cantrell et a1 Oct. 25, 1938 2,575,003 Caron et al Nov. 13, 1951 2,618,538 Jones et al Nov. 18, 1952 2,672,408 Bonner Mar. 16, 1954 

1. A PETROLEUM DISTLLATE FUEL OIL INCLUDING AT LEAST 10 PERCENT OF CRACKED HYDROCARBONS TO WHICH HAS BEEN ADDED FROM ABOUT 0.001 TO ABOUT 0.2 PERCENT BY WEIGHT OF A MIXTURE OF FROM 1 TO 3 PARTS OF DINITROPHENYL OCTADECYL SULFIDE AND FROM 1 TO 3 PARTS OF A ZINC SALT OF A PETROLEUM NAPHTHENIC ACID HAVING A MOLECULAR WEIGHT OF FROM ABOUT 150 TO ABOUT
 300. 